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Tue Feb 23, 2010 2:02 pm

The tach should be plugged into the "-" or "1" side of the coil along with the green points wire.

Sometimes stray voltage or electrical "noise" will cause the tachometer to go wild. The fix is to install a diode before the the meter up on your dash. I put mine right at the coil as it was easy to do.

The points replacement module picks up the signal at a different spot on the distributor shaft than the points do. Re-time when switching back and forth.

From e-gauges.com....

Will VDO tachs work with points ignition or Pertronix?

Answer: Yes, with diode in line on the signal lead. Instructions are as follows:
Purchase a diode #1N4005 from a local electronics store such as Radio Shack or Circuit City. Cut both ends of the diode so each is approximately 3/4” long. Crimp 1/4” female spade connector on the end of the diode with the silver band. Crimp butt-splice connector on the other end of the diode. Crimp the opposite end of butt-splice connector to the wire connected to the ignition signal source. Connect 1/4” female spade connector used in #3 above to terminal #4 on the back of the tachometer. Connect a ground (-) wire to terminal #3. Connect a switched 12-volt power wire to terminal #2. Set switches for appropriate amount of cylinders

Also the mechanical fuel pump this thing came with is 1) a nightmare to replace with the engine in the car and 2) really expensive to buy a new one. Most people install an electric rotary fuel pump but most people just wire them to the "+" pr "15" side of the coil which is bad and can sometimes cause engine running problems (namely dying out or poor running when the coil cannot produce the elcectricty needed to run both the engine and the fuel pump). They would be far better off to power up the fuel pump via a fused relay like this one...

http://www.germansupply.com/home/customer/product.php?productid=16928&cat=&page=1

Tue Feb 23, 2010 2:05 pm

mook wrote: busdaddy wrote: First off find another mechanic, WOW :shock:
because he didn't time it or can't find the fuel pump? (or both?)
He seemed sure there was no mechanical fuel pump on there... :?

busdaddy wrote: As for the tach? Try disconnecting it and see how it runs.
am I right in thinking it runs off a wire to the coil? there's a green one which seems to run forward. are you thinking it could be causing it to run bad?

Both, a bus fuel system is simple and small, if he can't spend a minute on his back to trace the single hose from the tank what other more important jobs is he too lazy or daft to accomplish?

The tach should be connected to the - or #1 terminal on the coil along with the wire from the points or module, and I am indeed thinking it may be causing a problem, it's easy to try anyways.

Tue Feb 23, 2010 2:16 pm

thanks guys.

I will try disconnecting the tach tomorrow.
and may just consider finding a different mechnic

Tue Feb 23, 2010 5:07 pm

mook wrote: All of the above are fine. But certainly could not have changed dramatically in the space of a few hours.
The intermittant nature of the problem suggests it's not those to me.
Carbs are delortos. And again, were running fine until friday afternoon.
The problem appeared after the mechanic had tested the alternator. (He found no problems other than the regulator)

"The problem appeared after the "mechanic" tested the alternator?" He can't find the fuel pump? According to him the fuel pressure is low? What is the reading? Ya, I think I would find a different mechanic. :-k :bay_red:

Wed Feb 24, 2010 12:17 am

Well,

I unhooked the tach. No difference that I can see.

Started fine this morning ran well on the way into work. Then it stalled at the lights. I started it again, the dashboard lights stayed on, Ran normally for about 20 seconds, then it began to run rough and eventually spluttered to a halt.

I opened up the back and as usual couldn't see anything wrong shook a few wires, pushed a few spade connectors on tighter, tried again
No joy. Turning over healthily, but still feels like it's starved of fuel.

(I would immediately say fuel problem. But that doesn't explain the dash lights staying on in the moments before it begins to die.)

So after a few goes, it starts up and runs fine, all the way into work.

I... Don't... Have... a... clue... :? :( :?:

Wed Feb 24, 2010 2:34 am

Find some one who knows what the hell they are doing with an aircooled vw engine.He could not find the fule pump?Run fast!

Wed Feb 24, 2010 2:54 am

You are fuel starved.Check the fuel filter first.

Wed Feb 24, 2010 4:38 am

If it were me I would take my handy little screwdriver with me and when it died, I would remove the tops of thecarbs to see if there is any fuel in the float area.

Those "idiot lights" in the dash lights are coming on because the engine is running below the correct idle speed of about 850 RPMs. Oil pressure <6 psi and voltage less than 12.

Is there anyone around you that has an ACVW? I would ask them where they go for fixing.

Wed Feb 24, 2010 5:08 am

Hoody wrote: You are fuel starved.Check the fuel filter first.

Fuel filter is clean and clear

Wed Feb 24, 2010 5:10 am

[quote="Randy in Maine"]Those "idiot lights" in the dash lights are coming on because the engine is running below the correct idle speed of about 850 RPMs. Oil pressure <6 psi and voltage less than 12.[quote]

They stay on even when revving high. that's how I know the bus is about to come to a stop.

Seems to me that whatever is causing the dash "Idiot" lights to stay on, may also be preventing power to the fuel pump.

just need to find out what.

Wed Feb 24, 2010 7:27 am

How is the adjustment on the automatic choke?

Wed Feb 24, 2010 7:37 am

OK Mook you are going to have to explain to us just what kind of fuel pump you have in there. If it is an electric pump? Where does it derive its power from? Can you test the voltage it is seeing?

If it is indeed an electric pump, does the problem go away when you direct wire it to the battery for testing purposes?

Does a new fuel filter help the problem? Can you cut open the old filter to see if it is full of rust?

A cheap vacuum/0-10 psi fuel pressure gauge when hooked up to the fuel pump (be it mechanical or electricals) will tell us the fuel pressure it is putting out. They look sort of like this....

http://www.actron.com/product_detail.php?pid=16176

Lot of these were hooked up to the "+" or "15" side of the coil and when voltage is called for , the coil cannot always deliver.

Your volt ohm meter is going to pay off big time here. Hopefully yours has a dwell tachometer in it also.

http://www.amazon.com/Actron-CP7677-Automotive-Tro...mp;sr=8-10

You also need to be able to verify that you are indeed seeing correct oil pressure (when you stick a mechanical test gauge in the oil pressure switch sending unit hole).

That looks sort of like this....

http://www.summitracing.com/parts/VDO-153003/

If you need any of that stuff and cannot find it locally, PM me and I will see if I can do a "care package" to you.

One more thing.....

I see that this is Tim's "satchmo" old bus and he had it swapped over to dual dels and some sort of electric primer pump. I am not exactly sure how he had it set up. Perhaps a PM to him may help clarify just how it is set up.

Wed Feb 24, 2010 8:39 am

Not sure exactly what could cause both your charge light and oil pressure light to come on at the same time. They are wired somewhat differently. If your alternator is shorting out it would cause most of your problems.

Did you put in a new or factory rebuilt Bosch alternator when you were having charging problems? I would take a shot at it and say that your diode plate is intermittently shorting out to the cover plate. This is a common problem that Bosch seems to have no desire to admit to or fix. It greatly tarnishes their reputation.

Wed Feb 24, 2010 9:16 am

Is it indeed the oil light that's coming on or just the charge light and brake warning light but the oil light stays out? (I realise when this is happening you are more concerned with where to pull over than staring at your fuel gauge).

While you are looking at the wiring park the bus with one wheel up on the curb, crawl under the back and find the starter (I recall you having some starter issues a while ago so you know where that is :wink: ). Just above the starter is the fuel line coming from the tank, follow it and see where it leads (careful, it may be brittle, don't be rough with it). Double check all the connections at the starter terminals while you are under there as well.

Wed Feb 24, 2010 11:08 am

Randy in Maine wrote: OK Mook you are going to have to explain to us just what kind of fuel pump you have in there. If it is an electric pump? Where does it derive its power from? Can you test the voltage it is seeing?
Don't know what kind of pump. suspect electric and suspect it's behind the firewall

Randy in Maine wrote: I see that this is Tim's "satchmo" old bus and he had it swapped over to dual dels and some sort of electric primer pump. I am not exactly sure how he had it set up. Perhaps a PM to him may help clarify just how it is set up.
indeed it is. thought about PMing him, but "sold as is" and all that...
didn't come with aftercare.

Wed Feb 24, 2010 11:09 am

Wildthings wrote: Not sure exactly what could cause both your charge light and oil pressure light to come on at the same time. They are wired somewhat differently. If your alternator is shorting out it would cause most of your problems.

Did you put in a new or factory rebuilt Bosch alternator when you were having charging problems? I would take a shot at it and say that your diode plate is intermittently shorting out to the cover plate. This is a common problem that Bosch seems to have no desire to admit to or fix. It greatly tarnishes their reputation.
the oil light doesn't come on, sorry if I wasn't clear.
the generator light and the charge light come on.

no new alternator it was just the regulator, i was unlucky and got two duds.

Wed Feb 24, 2010 11:13 am

busdaddy wrote: Is it indeed the oil light that's coming on or just the charge light and brake warning light but the oil light stays out? (I realise when this is happening you are more concerned with where to pull over than staring at your fuel gauge).

While you are looking at the wiring park the bus with one wheel up on the curb, crawl under the back and find the starter (I recall you having some starter issues a while ago so you know where that is :wink: ). Just above the starter is the fuel line coming from the tank, follow it and see where it leads (careful, it may be brittle, don't be rough with it). Double check all the connections at the starter terminals while you are under there as well.

yup I recently replaced the "+" cable to the starter, and checked again when looking at ground strap. So confident that all connections ok.
everything seems to be in order under there.

Anyway It's in with an electrician tomorrow. I can't afford days off work to look at this, so cheaper to pay an expert.

Many thanks for all your help and suggestions though. I will let you know the outcome if any

Thu Feb 25, 2010 12:27 pm

So she's back and appears to be running fine.

Story from the guy: THe fuel pump was powered off the + side of the regulator, Putting strain on the Reg, and possibly causing it to blow.
The recent problems are due to there not being enough voltage to power the fuel pump and trigger the regulator at the same time.

I don't know why this only became a problem after he changed the regulator last week. (or do I?)

My theory: While changing the regulator, some of the connections broke/became loosened. I think this explains the intermittant nature of the problem and the fuel starvation and dashboard light situation.

either way. the fuel pump is now rewired to run from a different source, and it looks like the connections at the reg have been renewed/replaced.

He didn't charge me for this work, so maybe he felt a little responsible. who knows

here's hoping it's sorted.